Unfortunately, I've had my fair share of mangas that I've had the "what the.....?!?" reaction to. Among those, the ones I remember right now are Desire Climax (STAY AWAY!!!! Aggghhh!! Just so bad...) and watashi ni xx shinasai, which just gets more and more downright ridiculous the longer you read it. So just don't. I know there are way more....even crazier...but I can't seem to recall any of them at the moment. I'm convinced it's a self-preservation mechanism in order to protect myself from the tragic horrors of mangas gone bad.

Pastel was really good up until they got together, but since then it's literally been 50+ chapters of the SAME EXACT THING with no progression what so ever.

One Piece. It just lost me. Aside from Luffy and Zolo I couldn't care less about any of the characters. Before anyone says anything, I am in no way saying One Piece is bad. It just didn't grab me personally.

Wolf Crest. It was really interesting until it basically turned into rape fetish porn for about 15 chapters(no it wasn't hentai or even ecchi to start with) If that's your thing, fine, but don't inject it into your manga 50 chapters in when people are invested in your story and characters and there was no indication of stuff like this in the beginning.

I really hate giving up on something I've started, but I had to give up on Lovely Complex in the middle of volume 8. I just got so sick of the back and forth "Oh he loves me!"/"No he doesn't!" nonsense.

Monochrome Factor - Started off good, but then I found out it had the worst ending and I immediately stopped reading the manga. One of the main character dies, but they decide to not being him back while the villains get revived. To make it worse they decide to wipe his existence from everone's memory like he never existed. And he was the comedic relief character that everone picks on... WTF.

Ai Ore..gave 3 vols a chance but it just kept getting worse. I hated really hated Akira. He was so annoying and not very attractive. Just didn't understand why Mizuki would be attracted to him and not just ditch him from the get go.